Prevalence of Rickettsia species in ticks including identification of unknown species in two regions in Kazakhstan.

BACKGROUND: Over 60 years ago clinical patterns resembling tick-borne rickettsioses have been described for the first time in Kazakhstan. Since 1995 the incidence of clinical cases of tick-borne rickettsioses in humans seems to be rising but studies on epidemiological data regarding the occurring etiological agents, tick vector species, prevalence and distribution throughout Kazakhstan are still scarce to date. The aim of the study was molecular investigation of ticks for spotted-fever group rickettsiae in the endemic Kyzylorda region and the so far considered as non-endemic Almaty region. A total of 2341 ticks was collected in the two regions in Kazakhstan and sorted in 501 pools: Ixodes persulcatus (243); Dermacentor marginatus (129); Haemaphysalis punctata (104); Hyalomma asiaticum (17); Dermacentor reticulatus (3); and Rhipicephalus turanicus (5). Pools were tested for Rickettsia spp. using real-time PCR. For positive samples multilocus sequence typing (MLST) was performed. RESULTS: The calculated minimum infection rate (MIR) for rickettsiae in the investigated ticks in Almaty region varied between 0.4-15.1% and 12.6-22.7% in the Kyzylorda region. At least four different Rickettsia species were identified in the two selected regions of Kazakhstan. Two of these are already known to science: Rickettsia raoultii and R. slovaca, the latter being reported for the first time in Almaty region One new form, "Candidatus R. yenbekshikazakhensis", was described by MLST of six gene fragments in Almaty region and one new genotype, "genotype R. talgarensis" was detected using three gene fragments. CONCLUSIONS: Kazakh physicians should be aware of rickettsioses after tick bites in both regions studied. Both, R. raoultii and R. slovaca should be included in the diagnostics. The role for human diseases has further to be investigated for the newly described rickettsiae, "Candidatus R. yenbekshikazakhensis" and "Genotype R. talgarensis".

Seroepidemiological and molecular investigations of infections with Crimean-Congo haemorrhagic fever virus in Kazakhstan.

OBJECTIVES: The aim of this study was to detect the seroprevalence of Crimean-Congo haemorrhagic fever virus (CCHFV) in patients with fever of unknown origin (FUO) in endemic (Kyzylorda) and non-endemic (Almaty) oblasts of Kazakhstan. METHODS: Paired serum samples from 802 patients with FUO were collected. Serum samples were investigated by ELISA to detect IgG and IgM antibodies against CCHFV. Sera with suspected acute infection were further investigated by RT-PCR to detect the viral RNA. RESULTS: IgG antibodies were detected in 12.7% of the sera from both oblasts. Acute infection was shown by IgM ELISA in four patients from Kyzylorda, with only one developing severe CCHF. Viral RNA was found by RT-PCR in the other three patients' sera. Phylogenetic analysis of partial L and S segments revealed CCHFV genotype Asia 2 and a possible reassortment between the genotypes Asia 1/Asia 2. Animal husbandry, such as working with cattle and horses, was significantly associated with CCHFV seropositivity. CONCLUSIONS: The antibodies and viral RNA detected in sera indicate that mild or even asymptomatic CCHFV infections are presented in Kazakhstan. This study describes the circulation of CCHFV in the so far non-endemic Almaty oblast for the first time. In conclusion, physicians treating patients with FUO in Kazakhstan should be aware of mild CCHF.